WEDNESDAY, Oct. 3 (HealthDay News) -- Researchers say they have developed a blood test that could potentially detect hundreds of genetic conditions in newborn babies in about two days. The test might allow physicians to quickly diagnose babies and treat them instead of waiting for lengthy tests or guessing without full information.

The test, which uses a drop of a newborn's blood to examine the entire genome, isn't ready for widespread use. A study released Oct. 3 reports only the results of testing that confirmed genetic conditions in three newborns.

The test could be available soon, however, said study co-author Dr. Stephen Kingsmore, director of the Center for Pediatric Genomic Medicine at the Children's Mercy Hospital in Kansas City, Mo.

"Genome analysis is moving from being a research tool that holds promise to being something that's ready to ... be used for real medical care in real patients," he said.

Newborns routinely undergo genetic screening in the United States to see if they have genetic conditions. The screenings, however, look for about 60 conditions at most, Kingsmore said, and focus on diseases that don't show obvious symptoms at first.

There are thousands of other genetic conditions -- many of them quite rare -- and about 500 can be treated. If a child shows symptoms of one of them, testing may take weeks and cost thousands of dollars, Kingsmore said. Physicians may base their diagnoses on other factors in order to treat children quickly, in some cases to keep them from dying.

"The reality is that neonatologists have to treat on the basis of their best clinical judgment rather than based on any knowledge of the genome sequence," Kingsmore said.

"If you liken testing to fishing, conventional fishing is like throwing a line into the ocean and hoping you catch a fish," he said. The new test, which looks for signs of genetic problems throughout the genome, "is like throwing a net over the entire ocean and seeing what you catch."

The test costs about $13,500 and takes 50 hours to process, although researchers hope to quicken the pace, he said. The new study reports that the test identified genetic conditions in three newborns and ruled them out in another.

The study disclosed that several co-authors are employees of the company that makes the gene-sequencing instrument.

The study authors plan more research into the test, which looks for 3,500 signs of genetic problems. Kingsmore said the test could become available next year.

Dr. Avroy Fanaroff, chairman of neonatology at Cleveland's UH Rainbow Babies & Children's Hospital, who was not associated with the study, said the test is promising even though the new study is small.

"The authors proved that it is technically feasible to get a rapid turnaround time and prompt diagnosis, paving the way for specific therapy," he said.

The study appears in the Oct. 3 issue of the journal Science Translational Medicine.